Walter



Feb. 14, 1956 H. WALTER 2,734,578

METHOD AND APPARATUS FOR OIL RECOVERY Filed Feb. 14, 1952 '6 Sheets-Sheet 1 37 34- 23 H H H FUEL A w 325,, con a. P315 47 39 36 32 2| l3 l2 I9 20 4-4- 4.3- 42- PRIME o MOVER 3 GROUND LINE CAP ROCK HELLMUTH WALTER I INVENTOR.

Feb. 14, 1956 H. WALTER METHOD AND APPARATUS FOR OIL RECOVERY Filed Feb. 14, 1952 FIG. 3

6 Sheets-Sheet 2 HELLMUTH WALTER IN V EN TOR.

Feb. 14, 1956 H. WALTER 2,734,578

METHOD AND APPARATUS FOR OIL RECOVERY Filed Feb. 14, 1952 6 Sheets-Sheet 5 X INPUT WELLS =OUTPUT' OR PRODUCTION WELLS O OTHER WELLS HELLMUTH WA LTER IN V EN TOR.

Feb. 14, 1956 H. WALTER 2,734,578

METHOD AND APPARATUS FOR OIL RECOVERY Filed Feb. 14, 1952 6 Sheets-Sheet 4 FIG-.5 HELLMUTH WALTER IN V EN TOR.

Feb. 14, 1956 ER 2,734,578

METHOD AND APPARATUS FOR OIL RECOVERY Filed Feb. 14, 1952 6 Sheets-Sheet 5 HQ 6 HELLMUTH WALTER IN V EN TOR.

Feb. 14, 1956 H. WALTER 2,734,578

METHOD AND APPARATUS FOR 31L RECOVERY Filed Feb. 14, 1952 6 Sheets-Sheet 6 TEMPERATURE I /"9| -DISTANCE PUT OUTPUT wsu. WELI l l l l l. GAS AND SUPERHEATED STEAM ZONE 2. ADVANCING CONDENSING ZONE T K 3. GAS AND WATER ZONE T F|G.9

HELLMUTH WALTER IN VEN TOR.

United States Patent METHOD AND APPARATUS FOR OIL RECOVERY Hellmuth Walter, Upper Montclair, N. J., assignor 'to Worthington Corporation, Harrison, N. 1., a corporation of Delaware Application February 14, 1952, Serial No. 271,512

20 Claims. (Cl. 166-11) This invention relates generally to the problem of oil recovery and more particularly to a new method and apparatus for reducing the retentive forces holding the residual oil in oil-bearing sands or reservoir rock and for increasing the flow of such residual oil after the retentive forces are thus reduced so that a greater recovcry of oil can be effected from wells which have partly or wholly ceased producing.

It is well known in the art that the most eflicient methods of producing well, operation and control, wherein the natural formational energy, pneumatic induced-flow methods and various mechanical devices are primarily utilized, are incapable of securing more than a small percentage of the oil originally present in oilbean'ng formations. It is believed that the effect of these primary procedures will produce oil by flowing or pumping until an equilibrium is approached in the oil-bearing formation between the expulsive forces and the retentive forces acting on the oil in these formations and that no further change will occur unless the physical or chemical relations between the residual oil and the formation or rock strata are changed.

In an effort to recover the residual oil which remains when this equilibrium point is reached many secondary methods of oil recovery have been developed. These secondary methods are obviouslytherefore designed to unbalance the above mentioned equilibrium by either adding artificial energy to restore or replace the expulsive forces necessary to move oil into the producing well or by reducing the forces which resist the movement of the residual oil through the oil-bearing formation or strata or by a combination of both. Of these methods the most widely used are water flooding and various forms of gas and air drive or gas injection.

Water flooding which is common practice and widely used generally involves introducing water under pressure through one or more input wells, causing movement of a froth-like fluid of oil and water to other wells that are flowed or pumped for oil in the usual manner. Water operates by displacement moving the residual oil ahead of its advancing front which bank of oil is eventually forced from the reservoir rock into the producing wells. This method contemplates substituting artificial energy to force the capillary held oil from the oil-bearing formation.

In order to reduce the retentive effect of both capillary and adhesive held oil various modifications of this method have been undertaken such as heating the well or the injected water or utilizing preferential wetting agents such as a dilute solution of sodium carbonate, as sodium carbonate acts to reduce the interfacial tension between the residual oil and the immense surface area of the oil bearing sands or rock strata to which it adheres.

Gas or air drive and injection methods generally consist of one of the other of the following general types: (a) Pressure restoration wherein gas is forced into the productive formation at the locations which seem most favorable while all other wells are sealed until 2,734,578 Patented Feb. 14, 1956? pressure approximately equal to the formational pressure is restored throughout the entire oil bearing formation or strata; (b) pressure maintenance which is the above process applied to a field before the natural formational pressure is exhausted; and (c) pneumatic gas or air drive where gas is forced into the oil-bearing formation at certain selected wells referred to as input wells where conditions are favorable while simultaneously withdrawing gas and oil from other wells nearby referred to as producing or output wells. In this method either compressed air, natural gas, fluid gases, exhaust gases, etc., may be utilized and the residual oil in the oil-bearing strata is either carried along by or driven ahead of the injected gas or air flowing through the strata.

Referring to the pneumatic gas or air drive method, it has been found that the use of compressed air as a driving medium while successful in increasing the recovery of residual oil has also caused an increase in the viscosity of the residual oil which it is unable to force out due to oxidation of some of the residual oil by the oxygen present in the air medium. The effect of increased visccsity is to clog the pores of the oil-bearing formation or strata and prevent further recovery. In addition the use of compressed air has undesirable side effects such as the formation of explosive gases. This latter problem has been overcome by using the exhaust gases of internal combustion engines which While not as plentiful as air have been found to be considerably effective for the further reason that they contain a mixture composed chiefly of nitrogen and carbon dioxide. The nitrogen acts to provide the driving energy and the carbon dioxide tends to change the physical and chemical properties of the residual oil, in that it decreases viscosity, surface tension and the interfacial tension between the residual oil and the surface area of the oil bearing sands or reservoir rock.

While the above mentioned secondary recovery methods aid substantially in the recovery of residual oil from the oil-bearing formation or strata, there are various conditions which affect and limit the amount of oil recovered. For example, various portions of the oil-bearing strata are found to have dilfering degrees of porosity and permeability so that when fluids are injected into these areas at high pressures they will take the least line of resistance flushing out the highly porous permeable portions of the oil-bearing strata and leaving large bodies of residual oil unrecovered. In addition, where water is utilized as the driving agent, precipitations and emulsions may and do form which plug the pores as above mentioned in connection with the increase in viscosity caused by the oxidation of the residual oil by the oxygen in air when compressed air is used as the driving medium. Thus it is found that the present secondary methods used today fail or are unable to remove all of the residual oil from the oil-bearing formation or strata.

The present invention contemplates a method and apparatus designed to overcome these last mentioned disadvantages by reducing both the retentive forces acting on the residual oil and to furnish artificial energy to replace the formational energy for driving the residual oil to a predetermined output or producing well or wells to effectively recover all of the remaining residual oil in the formation or strata and relies primarily on the fortunate circumstance that a novel combustion chamber for combusting hydrocarbon fuels with air to produce tremendous heat and end products of nitrogen, carbon dioxide and water, when combined with water used as a coolant for the combustion chamber, will furnish a gas and superheated steam mixture which is at high temperature and high pressure and hence can be brought to the bottom of one or more suitable input wells and used as a driving medium to produce results either simultaneously, intermittently or alternately of all of the abovementioned secondary methods as will appear hereinafter.

It is another object of the present invention to provide a method and means for supplying heat to oil-bearing sands or reservoir rock by the smallest quantity of gas and superheated steam mixture because the quantitative intake of an input well is limited.

It is a further object of the present invention to provide a method and apparatus for supplying a gas and superheated steam mixture which can be easily changed so that it will have reducing properties to prevent oxidation of the residual oil or eliminate the same if already present.

It is pointed out that the preferred forms of this method and apparatus are shown and described generally for the application to input and producing well arrangements or for oil-bearing formation or strata whose depth is approximately 1800 feet. It will be understood, however, that the pressure indicated is therefore limited to this general level of the formation or rock strata. Actual pressures used will, of course, be varied, depending on the overburden (earth deposit) above the oil-bearing formation or strata. Thus, for shallow wells the pressure will be reduced to avoid fractures or faults or other disadvantageous results due to excessive pressures; conversely for very deep wells the pressures will have to be increased.

Accordingly, to perform this method the hydrocarbon fuel and air are individually passed into a novel combustion chamber at pressures between 1200-2000 p. s. i. a. and ignited. A water jacket forming part of the combustion chamber has its intake end near the ignition end of the combustion chamber to which water is fed or pumped at a pressure between 12002000 p. s. i. a. The water by heat exchange relationship will absorb the excess heat from the walls of the combustion chamber and will be delivered in its preheated condition into the combustion chamber at a mixing point remote from the ignition point where mixing of the nitrogen, carbon dioxide and water products of the fuel-air combustion under these operating conditions will form therewith a gas and superheated steam. mixture. at a temperature of approximately 400 to 500 centigrade and at a pressure of approximately 1400 p. s. i. The gas and superheated steam mixture is directed from the combustion chamber to the desired input Well or wells connected to the mixing end thereof and by reason of the high pressure will pass rapidly to the bottom of the input well so that there will be a relatively small loss in temperature to the casing through which it passes, proper insulation thereof against radiation and convection being assumed.

It is well known that heat is an excellent media for reducing the viscosity and surface tension of both capillary and adhesive held residual oil in the oil-bearing sands or reservoir rock. The fact that the intake of each well has a quantitative limit taken along with this makes this gas and superheated steam mixture highly desirable as it provides means for delivering the maximum amount of heat to the oil-bearing formation or strata by a relatively small quantity of gas and steam mixture, for when the gas and superheated steam mixture passes from the well into the surrounding sandsor reservoir rock at the formation or strata temperatures, and pressures, the gas and superheated steam mixture will be condensed, releasing its latent heat of vaporization to the sands or reservoir rock. Thus the latent heat of vaporization of the mixture acts as the heat-carrying agent, the maxi mum heat delivered being limited by the ability of the tube steel and its insulation through which the mixture passes and the minimtun heat secured being limited by the evaporation temperature which prevails at the formational pressures.

The advantages supplied by heat are believed to be further augmented by the presence of carbon dioxide as it has been found that when carbon dioxide is utilized at high temperature and high pressure as a component of the secondary recovery fluid that it appears to react in the formation of rock strata with certain of the constituent portions of the residual oil to produce unstable solvents or surface acting compounds, whereby the retentive forces due to capillarity, adhesion and interfacial tension between the formation or rock strata and the residual oil are reduced. The new compounds formed act either as solvents or displacing agents to aid recovery.

initially, of course, due to the differential temperature when the gas and superheated steam mixture reaches the bottom of the input well it will condense on the face of the oil-bearing formation or rock strata. As the process continues this condensing zone moves radially away from the input well so that as the process continues the oilbearing formation or rock strata will be under a constantly changing state of flow conditions to form generally three main zones which canbe distinguished; First, there will be a radially advancing superheated zone of about constant temperature. This zone will be completely free of water and nearly free of oil and the rela tive permeability will behigh because there is almost a single medium (gaseous) system present. Second, there will be a radially proceeding condensing zone with decreasing absolute and partial pressure. It is this zone in which the major residual oil removal is believed to occur due to gassifying various compounds of the residual oil and reducing the surface tension, viscosity and interfacial tension, the dual phase effect and possibly the CO2 in solution effect above mentioned. Third, a gas-water.

zone. This zone is, of course, steadily decreasing in volume, the temperature of the gas-water mixture will in this zone rapidly decrease to the output or production well giving. off its heat to the oil-bearing formation or rock strata.

These three zones are graphically illustrated in Figure 9 of the drawings.

In the present method and apparatus, it is often advisable to provide means for modifyingthe gas and superheated steam mixture where it is desired to avoid oxidation of the residual oil in the oil-bearing formation or strata with its resultant difficulties as abovementionedor if the residual oil has already been oxidized by previously applied water and air drives. This can be accomplished by regulating the ratio between the fuel and air such that by utilizing excess fuel during combustion the products thereof will include carbon which in the presenceof preheated water at high temperature and high pressure, with or without a catalyst will undergo the water gas reaction in accordance with the equations:

O +Hg0 CO +H:

CO +1120 COz-i-Hz-i-A drogen relationships can, of course, be varied by changing,

the ratio of the fuel-air mixture supplied to the combustion chamber, the temperature and the catalyst or any combination of these three to secure the desired ratio of the two gases as Well as the quantity of the sum of both as compared with the total quantity of the mixture.

In the present method and apparatus it may be found desirable to utilize or' remove one or more of the individual components of the secondary recovery fluid. This may be accomplished easily by various preferred forms of the invention hereinafter described. Since the gas and gas mixture are not required to be of high purity, the apparatus for the elimination of one or more of the gases will, as indicated in the drawings, be tively simple design.

of compara.-

In accomplishing the above method and objects of the present invention a preferred form of the apparatus consisting of various features and construction of parts are described in connection with the accompanying drawings in which:

Figure 1 illustrates a vertical section through a fragment of an oil field in conjunction with a diagrammatic form of the system and arrangement of the general apparatus for the practice of the present invention.

Figure 2 shows a vertical section taken through the type combustion chamber shown diagrammatically in Figure 1.

Figure 3 shows the combustion chamber in Figure 1 with interchangeable scrubbers partly in section.

Figure 4 shows a vertical section through a modified form of the combustion chamber for producing a gas and superheated steam mixture having reducing properties.

Figure 5 shows a vertical section through a modified form of the combustion chamber in combination with an arrangement for removing nitrogen from the gas and superheated steam mixture.

Figure 6 shows a vertical section taken through a modified form of the combustion chamber in combination with an arrangement for removing carbon dioxide from the gas and superheated steam mixture.

Figure 7 is a vertical section through a modified form of the combustion chamber in combination with an arrangement for producing only superheated steam to be utilized as the injected fluid.

Figures 8a, 8b, and 8c, shows various types of injection patterns which can be used with the present invention.

Figure 9 graphically shows the changing state of the gas and steam mixture as it moves through the oil-bearing formation or rock strata.

Referring to the drawings, Figure 1 shows an input well A and a producing or output well B. Only one of the input wells being selected for the purpose of illustrating the present method and apparatus comprising this invention, although it is understood that any number of input wells could be used as will produce the best results in accordance with well known practices in the art such as the five spot pattern or other arrangements as illustrated in Figures 8a, 8b, and 8c. 7

Input well A is shown as having a standard well casing 1 positioned therein in accordance with well known practices in the art in which an input conduit 2 is mounted and held concentric with the longitudinal axis thereof by means of distance rings 3. Insulation 4 is provided between the inner wall of the well casing 1 and the outer wall of the input conduit 2 to minimize heat loss through the wall of said input conduit.

The input conduit 2 extends outwardly of the surface end of the casing 1 through an airtight gland or packing 5. An end cover 6 connected to the surface end of the casing is provided to hold the gland 5 in position. A weighted rocker arm 7 is pivotally mounted at S and movably connected to suitable lugs 9 on the input casing to act as a support and means for removing the input conduit from the well casing if necessary. A suitable conical seat 9' being provided to hold the input conduit in position and prevent it from slipping into the well.

Connected to the end of the input conduit 2 at the point where it extends through the casing 1 is a flexible connecting conduit 10 having a main control valve 11 for controlling the flow of the gas and steam mixture therethrough. An auxiliary start-up valve 12 is also provided in the connecting conduit 10 and a pressure gauge 13 is disposed above both of said valves at a point between the valves and where the said connecting conduit 10 is attached at its other end to a heat and gas producer 14.

Heat and gas producer 14 forms part of the system or general arrangement diagrammatically illustrated in Figure 1 for supplying the desired gas and superheated steam mixtures abovementioned, it being understood that although the simplest type of heat and gas producer is shown in Figure 1 that one or theother of the modified forms thereof hereinafter to be described may be substituted therefor without departing from this preferred arrangement.

Referring to Figure 2, the simplest type of heat and gas producer 14 is shown having a main body 15 substantially cylindrical shaped forming combustion chamber 16 and closed at one end by a removable dome-like head or ignition end 17. A mixing chamber 18 is formed by a conelike end section 19 continuous with the main body 15 at the end remote from the head or ignition end 17, the vortex of the cone having a coupling means 20 to connect the heat and gas producer 14 to the connecting conduit 10 between the heat and gas producer 11 and the input conduit 2 in the input well A.

Surrounding the ignition end 17 and the main body 15 is a cooling jacket 21. The portion of the cooling jacket 21 about the head or ignition end 17 is provided with the cooling water intake 22 so that cooling water will initially flood the ignition or hottest end of the combustion chamber 16 to prevent the walls from disintegrating under continuous use. movable in the present construction a U-shaped connecting conduit 23 connects the portion of the cooling jacket 21 about the head or ignition end 17 with the portion of the cooling jacket about the main body 15. Partitions 24 are further provided in the cooling jacket portion about the main body 15 to impart a spiral movement to the cooling water as it moves downwardly about the main body to enable the cooling water to remain in contact a little longer with the walls of the combustion chamber and to increase the cooling water velocity so that it will be smoothly injected into the mixing chamber 15 in its preheated condition, through the cooling water outlets 25 circumferentially spaced on the combustion chamber wall just above the cone-like mixing chamber 18.

The mixing chamber 13 is further provided with one or more circumferential evaporation plates 26 disposed on the inner wall of the mixing chamber 18 below the outlets 25 so that cooling water if necessary may be held momentarily to absorb sufficient heat to be converted into the superheated steam state which is desired as is hereinafter described.

The combustion chamber is further shown as having at the head or ignition end 17 an air outlet 27 axially disposed with respect thereto and a fuel outlet 28 entering the air outlet 27 perpendicularly thereto and turning thereafter inside the air outlet axially so that it will run concentric thereto. Thus the fuel outlet 28 is disposed inwardly of the air outlet 26 to allow thorough intermixing of fuel and air fed into the combustion chamber 15.

A suitable ignition means 29 adjacent these outlets such as a spark plug or the like type of device will be required to ignite the mixture initially during the starting-up process and will act as an igniter until the temperature and pressure of the ignited mixture reaches a point where self-ignition will continue as fuel and air is fed to the combustion chamber through the air outlet 27 and fuel outlet 28 in the desired ratios. All of which is clearly shown in Figure 2.

Cooling water is conducted to the cooling water intake 22 through a water conduit 30 provided with a valve 31 to control the flow therethrough and connected at one end to the cooling water intake 22. The other end of the water conduit is attached to a suitable water pump 32 as is diagrammatically shown in Figure 1 of the drawings.

The water pump may be any suitable type pump capable of supplying the water at pressures between 1200-2000 p. at a. such as a reciprocating pump, easily purchasable on the open market. The pump will, of course, take its suction from any suitable source of available water (not shown).

The air outlet 27 is connected through an air conduit 34 having a valve 35 for controlling the flow of air therethrough which is in turn connected to the discharge of a Since the ignition end 17 is shown as remists suitable compressor 36 as; is diagrammatically shown in Figure 1 of the drawings. The air compressor 36 may be any suitable type which will deliver air under pressures between 1200-2000 p. s. i. such as a. reciprocating type compressor which typecompressor is easily purchasable on the open market. The air compressor 36 in addition will have its suction (not shown) open to atmosphere so that it will have a constant source of air available for compressing, it being understood that other gases which support combustion could be supplied by having the suction attached to a suitable source.

Thefuel outlet 28 is similarly connected through a gas conduit 37 having a valve 38 therein to control the flow of fuel gas therethrough which is in turn connected to the discharge of a suitable gas compressor 39 as is also shown in Figure l of the drawings. The fuel gas compressor may be any suitable type which will deliver fuel gas under pressure between 1200-2000 p. s. i. such as a reciprocating type compressor which compressor is easily purchasable on the open market. The fuel gas compressor 39 will of course have its suction connected to a suitable fuel reservoir (not shown) so that a constant source of fuel will be available for compressing.

The water pump 32, air compressor 36 and fuel gas compressor 39 may be driven by individual prime movers or as shown in the preferred arrangement in Figure l by a single prime mover 4-0 coupled directly to a driving shaft 41 connected through suitable pulley or gear trains 42, 43 and 44 to driven shafts 45, 46 and 47 on the water pump 32, air compressor 36 and fuel gas compressor 39, respectively, to provide operating means therefor. These power transmission devices are Well known in the power transmission art and are therefore not described in detail in connection with the present invention.

Operation In operation, for starting up, main control valve 11 is closed and the auxiliary start-up valve 12 is opened.

The prime mover 40 is thereafter started causing the driving shaft 41 to rotate the driven shafts 45, 46 and 47 on the water pump 32, air compressor 36, and fuel gas compressor 39 whereby water, air and fuel gas will pass to the respective suctions of the water pump 32, air compressor 36 and fuel gas compressor 39.

Water control valve 31 is first opened to allow cooling water to start flowing from the water pump 32 through the water conduit 30 to the cooling water intake 22 connected thereto. The cooling water will be forced downwardly through the cooling jacket 21 and out through the cooling water outlets 25 into the combustion chamber is through the mixing chamber 18 into flexible connecting conduit whence it passes through the auxiliary start-up valve 12 to a container or trap or over the earth for the short start-up period.

When the cooling water starts to flow out of the auxiliary start-up valve 12 the suction for the air compressor 36 and the fuel gas compressor 39 can be opened and cornpressed air and compressed fuel passed to the air outlet 27 and fuel gas outlet 28 through the respective air conduit 34 and fuel gas conduit 37 connected thereto by opening the air valve control 35 and fuel gas valve control 38. The air valve control 35 and the fuel gas valve control 38 can also control the desired ratio of air to fuel.

The. air and the fuel gas will pass into the combustion chamber 16 through the air outlet 27 and fuel gas outlet 28', and by reason of their position with respect to each other as above described will be thoroughly intermixed so that they can be ignited by means of the igniter 29.

Air and fuel gas under pressure are fed continuously to the combustion chamber 16 as long as the air control valve 36 and the fuel gas valve 33 are open and the air compressor 36 andfuel gas compressor 39 are inoperation. Accordingly, as the. mixture is fed to the combustionchamber 16 at increased pressures the temperature therein will be built up. As this occurs, the exhaust issuing from the auxiliary start-up valve 12. will contain more and more steam. therein by reason of. the heat, ex change relationship which, will be occurring across the wall of the cooling jacket 21.

Accordingly, as this occurs the auxiliary start-up valve 12 is slowly closed and the main control valve 11 is slowly opened substantially simultaneously therewith or approximately so, so that the gas and superheated steam mixture will be passed directly into the input conduit 2 and down the inlet well A to be brought into contact with the face of the oil-bearing formation or strata of the input well A.

After the combustion temperatures at the pressures at which the fuel and air are delivered to the combustion chamber as hereinafter described are sufiiciently high, the ignition means 29 is no longer necessary and may be turned off. ignition will thereafter continue spontaneously as long as air and fuel in the proper mixtures are delivered to the combustion chamber 16.

The present drawings indicate an oil-bearing formation in rock strata which is relatively deep. Relatively deep in the present application is understood to mean that the oil-bearing formation or strata is not open to the surface and that there is sufficient overburden (earth deposit) to allow for the application of pressure to the input well. The present invention is thus applicable to any oil-bearing strata which meets this requirement regardless of its actual measured depth. The total effect of variation and depth being merely to vary the applicable pressure conditions within the limits of the particular overburden above the oil strata.

In the formation indicated in the drawings, air and fuel gas are delivered to the combustion chamber 15 at high pressures between 14002000 p. s. i. a. or about to 136 atmospheres. This reduces the necessary volume of the combustion chamber to approximately of the volume required for combustion of a like volume of air and fuel gas at atmospheric pressure so that combustion products consisting of nitrogen, carbon dioxide, traces of oxygen, carbon monoxide and hydrogen will be very low in volume and still be at high temperature and high pressure.

The combustion temperature in the ignition end 17 of the combustion chamber 16 at the pressure in the combustion chamber 16 which by reason of the expansion of the air and fuel mixture will be slightly less the delivered pressure will be approximately 2000 C. This temperature would ordinarily cause the wall of the combustion chamber to disintegrate in a very short time. However, by reason of the cooling jacket 21 the cooling water absorbs a considerable amount of this heat. The cooling water will have to be delivered at a pressure in excess of 1400 p. s. i. so that it can be forced into the combustion chamber 16 through the cooling water outlets 25. At this pressure its velocity will be fairly high but it will nonetheless absorb SUfiiCieTli heat at this pressure so that as it passes into the combustion chamber all or substantially all of the cooling water will flash into steam and as it is thoroughly intermixed with the combustion products it will continue to absorb heat until there is an equilibrium between the products and the steam which in effect will superheat this steam.

Since the pressure in the well will be lower for input wells on which the present apparatus would be used, the

differential pressure between the combustion chamber 16 and the inlet well A will allow the gas and superheated steam mixture to expand rapidly through the connecting conduit 10 and input conduit 2 to the bottom of the input well A to bring the gas and superheated steam mixture into ducing or output well B which is at atmospheric pressure. the mixturewill be forced into the oil-bearing formation or strata. Since the temperature of the oil-bearing formaangers tion is about 27 C. the superheated steam will start condensing almost immediately surrendering its latent heat to the immediate portion of the formation about the inlet well A. This condensation point for the superheated steam will depend on the evaporation temperature for the steam at the partial pressure in the oil-bearing formation, and will of course advance radially through the formation as the area about the inlet well which is already heated is increased. The oil-bearing formation will thus form a series of declining isothermals into the unpenetrated portion of the oil-bearing formation or between the input well A and the producing or output well B as oil is recovered.

The rate at which the gas and superheated steam mixture can be pumped into the inlet well A will depend on many variables such as the permeability and porosity of the oil-bearing formation, the viscosity and surface tension of the oil, the interfacial tension between the oil and the oil sands or rock, the various different degrees of permeability between the dilferent strata of the oil-bearing formation and other variables. The rate will even vary from time to time for a particular input well by reason of these variables.

At the same time that the heating is taking place the carbon dioxide portion of the secondary recovery fluid will be acting as abovementioned to aid the recovery of the residual oil.

In effect, an oil bank will be formed as in the well known Water and gas drives above mentioned which under the action of the gas and superheated steam mixture will be moved slowly towards the producing or output well B. The producing well B can then be flowed or pumped by standard methods well known in the art and which do not form part of the present invention.

General arrangement with scrubbers Soot formed during combustion if in large enough quantities will act to clog up the pores in the oil-bearing formation or strata and may give other undesirable side effects. Accordingly, Figure 3 shows dual scrubbers which may be alternately inserted between the heat and gas producer 14 and the flexible connecting conduit 10.

Referring to Figure 3, the scrubbers 50 and 51 are shown as substantially identical in construction and include cylindrical outer chambers 52 and 53 having conical-shaped inlets 54 and 55 connected at one end to elbows 56 and 57 respectively, which elbows 56 and 57 are connected at their other ends to the outlets of a twoway outlet valve control 58 having its inlet connected to the coupling means 20 of the heat and gas producer 14. A handle member 59 for the two-way valve control 58 is manually positioned to pass the gas and superheated steam mixture from the mixing chamber 18 to one or the other of the scrubbers 50 and 51.

Since the scrubbers are substantially identical in construction reference is had to scrubber 50 which is shown in section in Figure 3 of the drawings to show the nature of the construction of both scrubbers.

Scrubber 50 is shown as including a cylindrical inner chamber 60 closed at the end remote from the inlet end of the cylindrical outer chamber and held in spaced relation with respect to said cylindrical outer chamber 52 by means of brackets 61 and a horizontal flange 62 about the open end of the cylindrical inner chamber adjacent the inlet end of the cylindrical outer chamber 52 whereby an annular chamber 63 will be formed therebetween. The cylindrical inner chamber 60 will be filled with small annular rings 64 such as Raschigs rings or the like type of device for filtering the soot from the gas and superheated steam mixture which Will be passed from the mixing chamber 18 through the two-way valve 58 elbow 56 to the inlet end of the cylindrical outer chamber 52 and thence through the rings 64 in the cylindrical inner chamber 60. -Circumt'erentially spaced outlets 65 are provided adjacent the closed bottom of the cylindrical inner chamber 60 which provides communication and flow means from the inner chamber through to the annular chamber 63 formed between the cylindrical inner chamber 60 and the cylindrical outer chamber 52, all of which is clearly shown in Figure 3 of the drawings.

An outlet 66 communicating with the annular chamber 63 is connected to a coupling conduit 67 which is in turn connected to the flexible connecting conduit 10 to provide means for leading the filtered and soot-free gas and superheated steam mixture from the annular chamber 63 to the flexible connecting conduit 10 whence it may be led to the input conduit 2 and the inlet well as above described.

General arrangement for a gas and superheated steam mixture having reducing qualiti s It may be desirable to produce a gas and superheated steam mixture having reducing properties. This may be done by modifying the heat and gas producer as is shown in Figure 4 of the drawings, it being understood that the general arrangement as shown in Figure 1 will remain the same except that the modified heat and gas producer 14' as shown in Figure 4 will be substituted for the heat and gas producer 14 and the operation will be modified by changing the fuel-air ratio to produce the desired result.

Referring to Figure 4, the modified heat and gas producer 14' includes a substantially elongated cylindrical main body 70 having a combustion chamber 71, a conically shaped water gas reaction zone 72 medially positioned in said main body and continuous with said combustion chamber 71 and a mixing chamber 73 continuous with said water gas reaction zone 72 remote from said combustion chamber. The cylindrical main body 70 is closed at the combustion chamber end thereof by a removable dome-like head or ignition end 74 identical in design and construction with that of the heat and gas producer 14, and accordingly is provided with air outlet 75 in the axial line thereof and a gas outlet 76 entering perpendicularly to the air outlet 75 and thereafter turning to lie concentric therewith. Suitable ignition means 77 is also provided adjacent the air outlet 75 and fuel gas outlet 76.

The air outlet 75 and fuel gas outlet 76 will of course be connected to air conduit 34 and fuel gas conduit 37 respectively of the general arrangement in Figure 1 as the present modified heat and gas producer 14' merely replaces or is substituted for the heat and gas producer 14 thereshown. As in the general arrangement above described air and fuel gas Will be supplied to the modified heat and gas producer 14' through the air conduit 34 and fuel gas conduit 37.

The mixing chamber end of the cylindrical main body 70 will also be provided with a connecting means 78 for connecting the heat and gas producer 14' to the flexible connecting conduit 10 shown in the general arrangement to enable the gas and superheated steam mixture produced in the modified heat and gas producer 14' to be passed to the flexible connecting conduit 10 and thence to the input conduit 2 so that it can be fed to the input well A, as above described in connection with the general arrangement.

A cooling water jacket 79 is similarly provided about the dome-like head or ignition end 74 and about the combustion chamber 71, the water gas reaction zone 72 and the mixing chamber 73 of the cylindrical main body 70 to prevent the walls of the combustion chamber for disintegrating under prolonged usage and to provide convenient means for preheating the water up to relatively high temperatures.

A cooling water intake 80 is provided in the wall of the cooling water jacket about the dome-like head or ignition end 74 so that the ignition or hottest end of the combustion chamber will be cooled first. The cooling water intake 80 will similarly be connected to the water conduit 30 shown in the general arrangement so that cooling water will be delivered'to the modified heat and gas producer 1,4 as above described in connection with the operation of the general arrangement shown in Figure 1. A U-shaped conduit 81 is necessary to connect that portion of the cooling water jacket about the dome-like head or ignition end 74 with the portion of the cooling water jacket about the cylindrical main body 70 so that cooling water may pass downwardly from the dome-like head or ignition end 74 about the main body 70. Partitions 82' are provided in the cooling water jacket to impart a spiral movement to the cooling Water to enable the cooling water to remain in contact with the walls of the cornbustion chamber 71, and to increase the velocity of the cooling water. so that it will be smoothly injected into the water gas reaction Zone 72 and mixing chamber 73 as hereinafter described.

The water gas reaction Zone 72 which is medially positioned in the main body 70 between the combustion chamber 71 and the mixing chamber 73 is substantially a. comically-shaped portion of the lower end of the combustion chamber and therefore has the Wide inlet portion of the cone continuous with the combustion chamber while the narrow restricted outlet 83 continuous with the upper end ofthe mixing chamber 73.

About the upper or wire end of the water gas reaction zone are a first group of relatively few circumferentially spaced cooling water outlets 84 which provide means for allowing a small portion of the cooling water to expand from the cooling water jacket 79 about the main body 70 so that it flashes into steam as above described in connection with the operation of the heat and gas producer 14. Similarly, evaporation plates 85 circumferentially mounted and in spaced relation along the water gas reaction Zone wall are provided to enable further absorption of heat by cooling water which does not flash into steam at once to enable it to pass to'the vapor phase.

The mixing chamber 73 will broaden in its upper portion from the restricted outlet 83 and then form a conically-shaped outlet 35' which communicates through the connecting means 7 8 with the flexible connecting conduit 19. A second group comprising a large number of circumferentially spaced cooling water outlets 86 are provided in the mixing chamber above the comically-shaped outlet 85 so that the greater portion of the cooling water can expand from the cooling water jacket '79 into the mixing chamber as above described in connection with the heat and gas producer 11. Evaporation plates 87 are also provided on this conical-shaped outlet 85 to enable cooling water to pass to the vapor phase.

The mixing chamber 73 is also provided with a transverseiy mounted semi-spherical perforated support plate 88 above the cooling water outlets 86 which supports thereon suitable catalytic material 89 such as ferrous compound and the like which act to catalyze the water gas reaction and which may be used along with the temperature to stabilize the carbon monoxide-hydrogen ratio of this reversible reaction.

Operation to produce a gas and superheated steam mixture having reducing properties When the modified heat and gas producer 14 is connected into the general arrangement in Figure 1 to replace the heat and gas producer 14 as above described the operation of the general arrangement as above set forth will remain the same insofar as starting up and bringing the heat and gas producer up to proper temperature and pressure to produce the desired result of furnishing a gas and superheated steam mixture.

However, where it is desired to produce a gas and superheated steam mixture with reducing properties the operation must be modified by regulating the air valve control 35 and the fuel-gas valve control 38 so that an excess amount of fuel will be delivered to the modified heat and gas producer 14', or by changing the delivery 12 volume of the compressors and pumps by changing. the speed.

In the presence of; excess fuel the combustion products will include nitrogen, carbon dioxide, carbon and some steam which will of course be at high temperature and high pr ssure, such that as it advances through the com bustion chamber 71 and the Water gas reaction zone 72' in the presence of the steam formed from the cooling water by expanding through the first cooling water outlets 84 it will undergo the Water-gas reaction in accordance with the reaction:

C H2O 0 O H2 This reaction is reversible. However, it is well known in the industrial arts for the preparation of large quantities of hydrogen and it has been found that high temperatures tend to move the action forward to produce a carbon monoxide-hydrogen ratio which generally is a function of the temperature and pressure and varies with changes thereof.

This gaseous product with reducing properties passed out of the restricted'outlet 83 into the mixing chamber 73 where the cooling water entering through the second" cooling water outlets 86 forms the gas and superheated steam mixture which will have reducing properties. same is passed through the connecting means 7% to the connecting conduit 10 and thence down well A through the input conduit 2 as above described in connection with the general arrangement.

Since this gas and superheated steam mixture will have reducing properties it will act to overcome the difficulties resulting from oxidation of the oil in the oil-bearing formation or strata or will actto prevent such oxidation from occurring.

General arrangement modified to eliminate one or more of the products of the gas and superheated steam mixture It may be desirable to eliminate carbon dioxide, nitrogenor both of these combustion products from the gas and superheated steam mixture. Accordingly, Figure 5 shows a modified arrangement for eliminating nitrogen; Figure 6 shows a modified arrangement for eliminating carbon dioxide, and Figure 7 shows a modified arrangement for. utilizing the combustion products to'produce only a superheated steam.

There will be substituted for the heat and gas producer 14 shown in the general arrangement in Figure 1 for each of the modified arrangements, a heat and gas producer 14" identical in each-of the Figures 5, 6 and 7 which comprises a cylindrical main body 99 having a combustion chamber 91 closed'at one end by a removable domelike head or ignition end 92.

Heat and: gas producer 14" accordingly for each. of the modified arrangements also includes air outlets 93 and'fuel outlets 94, the air outlet 93 being disposed axially in the dome-like head or ignition end 92 and the fuel outlet fit-entering the air outlet perpendicularly and then turning to lie axially therein and concentric of the air. outlet as above described in connection with the heat and gas producer. 14. The air outlet 93 is connected to the air conduit 34'and the'fuel outlet is connected to the fuel gas conduit 37 shown in the general arrangement in Figure 1 so that air and fuel gas in the proper ratiocan be fed to the combustion chamber 91.

A. suitable ignitionmeans 95 is provided adjacent theair outlet 93 and fuel gas outlet 94 for starting up.

In each instance the main body and the removable dome-like head-or ignition end 92 is surrounded by acooling jacket 96, that portion about the dome-like head or ignition end 92:beingconnected to the portion about the mainbody 90 by a U-shaped' conduit 97.

An upper coolingwater-inlet 98 in the dome-like head or ignitionend 92 and a lower cooling water inlet 99 at The a point remote from the head or ignition end 92 are provided to bring cooling water to the heat and gas producer 14" at two points. The upper and lower cooling water inlets 98 and 99 are connected by a T-coupling 100 and an elongated elbow-like conduit 101 so that the cooling water can be brought through one side of the T-coupling 100 as at 102. The water will by reason of the orifice 103 in the lower cooling water inlet 99 be directed mainly into'the upper cooling water inlet 98 only a small percentage of the water being allowed to pass through the orifice to the lower and cooler portion of the cooling jacket about the heat and gas producer 14", as is clearly shown in Figures 5, 6 and 7 in which the heat and gas producer 14" are the same.

At a medial point in the cooling water jacket 96 about the main body 90 of the heat and gas producer 14", a gas and superheated steam outlet 104 is provided which is connected by coupling means 105 to the flexible conduit 10 shown in the general arrangement in Figure 1. Thus the gas and superheated mixture formed or if just a superheated steam as hereinafter described with respect to Figure 7, can be passed from the outlet 104 to the flexible conduit 10 and thence down the input conduit 2 of the input well A as above described.

The heat and gas producer 14" shown in Figures 5, 6 and 7 will also include an exhaust outlet 106 at the end of the combustion chamber 91 remote from the dome-like head or ignition end 92 which has a coupling means 107 for coupling the heat and gas producer 14" to various additional elements hereinafter described depending on whether the operator desires to remove nitrogen such as is shown in Figure 5, carbon dioxide as is shown in Figure 6 or for producing only superheated steam as is shown in Figure 7 of the drawings.

Removal of Nitrogen The removal of nitrogen is accomplishedby a separation process in which the combustion products are passed through an absorbing tower in countercurrent flow with the cooling water. At the high pressure and at the temperature which will prevail carbon dioxide will be selectively absorbed while the nitrogen will pass therethrough being substantially insoluble, so that it can be passed to atmosphere as waste, collected as a by-product if economically feasible or used. as a pneumatic drive along with the gas and superheated steam mixture as a further step if found necessary. The countercurrent cooling water will then be passed as the cooling agent about the combustion chamber of the heat and gas producer 14" to form superheated steam which frees the carbon dioxide yielding a gas and superheated steam mixture substantially free of the nitrogen forming part of the original combustion products.

Referring to Figure 5, this type of apparatus is shown wherein the coupling means 107 of the exhaust outlet 106 on the heat and gas producer 14" is connected to one end of a connecting conduit 108 which is in turn connected at its other end to the combustion gas inlet 109 of an absorbing tower 110.

The absorbing tower 110 is a hollow elongated cylindrical enclosed tank member having the combustion products inlet 109 at its lower end so that combustion products will be forced upwardly through a cone-like injection nozzle 111 into the elongated absorption chamber 112 extending the greater portion of the remaining length of the absorbing tower 110. Spaced above the cone-like injection nozzle 111 and transversely mounted across the elongated chamber 112 is a perforated support plate 113 which receives thereon round metal non-reactive devices such as annular rings and the like type of surface increasing device. The surface increasing devices being disposed so as to substantially fill that portion of the absorption chamber 112 above the perforated plate 113, as is clearly shown in Figure of the drawings.

Countercurrent flow is effected by gravity on the cooling water which enters through a cooling water inlet 115 at the upper end of the elongated chamber 112 connected to the water conduit 30 shown in the general arrangement of Figure l. The valve 31 will control the flow of cooling water therethrough as above described in connection with the operation of the general arrangement. The cooling water outlet 116 is at the lower end of the elongated chamber 112 at the spaced portion thereof between the cone-like injection nozzle 111 and the perforated plate 113. The cooling water outlet 116 is connected to the point 102 on the T coupling to allow cooling water to flow from the absorbing tower to the cooling water jacket 96 through the cooling water inlets 98 and 99 thereof as above described.

A water sight gauge 117 is also conventionally mounted and communicates with the elongated chamber 112 through the lower water gauge conduit 118 and the upper water gauge conduit 119, the upper water gauge conduit 119 being disposed above the cooling water inlet of the absorbing tower 110, so that the level of the fluid in the absorbing tower 110 can be read on the sight gauge, as is clearly shown in Figure 5 of the drawings.

A gas outlet 120 at the uppermost end of the elongated chamber 112 is connected to an exhaust conduit 121 provided with a suitable control or expander valve 122 so that the back pressure in the elongated chamber 112 of the absorbing tower 110 can be properly controlled. The exhaust conduit 122 can be opened to atmosphere or can be directed to a suitable reservoir (not shown) if it is desired to collect the non-absorbed gases from the absorbing tower 110.

Operation of the general arrangement with nitrogen removal The heat and gas producer 14" and the absorbing tower 110 are placed in the general arrangement shown in-Figure 1 in place of the heat and gas producer 14, by connecting them to the elements 10, 37, 34, and 30 as described above. The system is otherwise unchanged.

Accordingly, for starting up, main control valve 11 is closed and the auxiliary start-up valve 12 is opened. All other valves are normally closed.

The prime mover 40 is thereafter starter causing the driving shaft to rotate the driven shafts 45, 46 and 47 of the water pump 32, air compressor 36 and fuel-gas compressor 39 whereby water, air and fuel-gas will pass to the respective suctions of the water pump 32, air compressor 36 and fuel-gas compressor 39.

Water valve 31 is then opened and the system is flooded and regulated to allow the water to reach a level in the absorption tower 110 and hence the combustion chamber 91 connected thereto through the connecting conduit 108 indicated by the point P on the water sight gauge 117.

This will leave a relatively small combustion space in the combustion chamber and, accordingly, combustion is commenced relatively slowly and under low pressures by opening and regulating the valves 35 and 38 to admit air and fuel gas through conduits 34 and 37 through the air outlet 93 and gas outlet 94 connected to these respective conduits, and the same is ignited by the igniting means 95. As combustion progresses in the combustion chamber 91, the water level therein will be slowly lowered with the slow increase of pressure until the combustion chamber 91, the connecting conduit 108 and the cone-like-injection nozzle 111 are. free of cooling water. The combustion products will have sufiicient pressure to prevent the water from entering the cone-like injection nozzle 111 and will, as the pressure mounts higher, be forced upwardly through the downwardly descending cooling water. Combustion continues under slowly increasing pressure until the back pressure of the collected combustion gases start to force the level of the water in the absorbing tower 110 indi-- catedat P on the suction sight gauge 117 downwardly. The level of the water can be maintained at the point 'P by regulating the back pressure with the control or exgra ers 1'5 pander valve 122 in accordance with empirical attempts to' suit the apparatus.

The operating pressure best suited "for securing the desired results-will be reached when the back pressure exerted by the non-absorbed combustion products-passing through the control or expander valve 122 are about-1400 p. s. i. a. When this pressure is reached it \villbe found that the air and fuel-gas must be brought into the combustion chamber 91 at about 1500p. s. i. a., at which pressures combustion will continue spontaneously aslong' as airfuel in proper ratio are fed to the combustion chamber.

When operating conditions are reached the combustion products will pass out of the combustion chamber 91 by' differential pressure relationship between the combustion chamber 91" and the absorbing tower 110 through the outlet 106 and connecting conduit 108 to the cone-like injection nozzle 111 whence they-pass upwardly through the elongated absorption chamber 112' in the absorbing tower 110' in countercurrent flow relationship with the continuously flowing cooling water entering at'the cooling water inlet 1'15 and descending by-force of gravity to the cooling water outlet 116.

At the increased pressure nearly all the carbon dioxide willbe absorbedin the cooling water while the remaining combustion products comprising, namely, nitrogen being only slightly soluble, can be passed out through the gas outlet 120 of the absorption chamber 112-as'the waste or non-absorbed gas.

The carbonated cooling water flows from the lower section of the absorption chamber 112 through the coolingwater outlet 116 to the T coupling 100 whence by reason of-the orifice 103, only a small'quantity is allowed to pass therethrough to the lowercooling water inlet 99 of the cooling water jacket 96. The remaining and greater portion of the carbonated water passes through the upper cooling water outlet 98' into the portion of the cooling.

water jacket 96 about the dome-like heador ignition end 92 ofthe heat and gas producer 1 In the cooling water jacket by heat exchange relationship the carbonated water will be heated to the vapor state of superheated steam which will in turn release the carbon dioxide gas absorbed in the absorbing tower 110V whereby a gas and superheated steam mixture substantially free of nitrogen will be obtained;

When the gas and superheated steam mixture starts to pass from the outlet 104 on the heat and gas producer 14" to the flexible connecting conduit the auxiliary start=up valve 12 may be regulated in accordance with the mixture of fiuid and steam which is issuing out of the waste outlet which is opened thereby, the auxiliary start-up valve 12 will then be slowly closed and the main valve 11 opened as the gas and superheated steam mixture increases until a gas and superheated steam mixture substantially free of; nitrogen will be passing to the input conduit 2 in the input well A where it can act on the residual oil to be recovered from the oil-bearing formation or strata similar to a pneumatic drive with the added properties and eifect of the heating of the oil-bearing formation or strata as above described in connection with the general arrangement as shown in Figure 1.

Removal ofcarbon dioxide While it is understood that the removal of carbon dioxide will eliminate one of the active agents in the gas and superheated steam mixture, it may be necessary to utilize such gas and superheated steam mixture and accordingly the apparatus to produce a gas and superheated steam mixture substantially free of carbon dioxide is shown in Figure 6 of the drawings.

The removal of carbon dioxide is accomplished by a separation process in which the combustion products are passed through an absorbing tower in countercurrent flow with. the cooling water. temperature which will prevail carbon dioxide will be selectively absorbed while the nitrogen will remain sub- At the high pressure and at the 1:5 stantially insoluble and pass therethrough. The carbonated water formed is then passed to an expander to release the carbon dioxide and thereafter returned under pressure to the inlets for the cooling jacket of the heat andgas producer. In the cooling jacket the cooling Water willbe changed to the superheatedsteam state. Nitrogen may be joined to the cooling water at the inlet side of the cooling jacket or at the outlet side by passing it from the absorbing tower to one or the other of these points as hereinafter described. The total result at either point will be that at the outlet-a gas and superheated steam mixture will be formed substantially free of the carbon dioxide forming part ofthe Original combustion product.

Referring to Figure 6, this type of apparatus is shown wherein the coupling means 107 of the exhaust outlet106 on-the heat and gas producer 14" is connected to one end of a connecting conduit 108 which is in turn connected at its other end to the combustion gas inlet of a carbon dioxide absorber 131.

The absorber 131 is a hollow elongated cylindrical tank member having thecombustion product gas inlet 130 at its lower end-ands gas outlet 153 at its upper end for non-absorbed combustion gases which are forced therethrough. Spaced above the inlet in the medial portion of the carbon dioxide absorber 131 is an absorbing chamber 133 formed by a transversely mounted perforated support plate 134which carries round metal or other non-reactive devices 135 such as annular rings for increasing the surface area in which absorption of cooling water to be brought in countercurrent flow with incoming combustion products willoccur. The surface increasing devices 135 are disposed to substantially fill the absorbing chamber 133zin the carbon dioxide absorber 131.

Countercurrent flow is effectedby gravity on countercurrent water which enters through a countercurrent water inlet 136 at the upper end of the absorbing chamber 133. The countercurrent water is delivered to the countercurrentwater. inlet 136 by a pump 137 of any suitable type whichhas its discharge connected thereto by a discharge conduit 138 and its suction to any suitable source such as a reservoir 139 by a suction conduit 140. A suitable valve 141 in the. suction conduit will control the flow of water to the pump 137. The pump may be any suitable type such as a centrifugal pump easily purchasable on the open market and accordingly not described in connection with the present invention. The countercurrent water outlet 142 for the absorbing chamber 131 on the carbon dioxide absorber 131 is at the lower end thereof just above the perforated plate and will receive the countercurrent water after it passes downwardly by gravity flow over the surface increasing devices 135. The countercurrent water outlet 142 passes the countercurrent water to an outlet conduit 143 connected at one end thereto and at the other end to an open reservoir 144. An expander valve 145 is provided in the outlet conduit 143 so that the pressure of the non-carbonated countercurrent water which will be passing from the outlet can be reduced to release the carbon dioxide therefrom. The suction (not shown) of the water pump 32 shown in the general arrangement will be connected through conduit 146 which communicates with the open reservoir 144 and will be the source of cooling water from the heat and gas producer 14." as hereinafter described.

A water sight gauge 151) is also conventionally mounted and communicates with the absorbing chamber 133 through an upper water gauge conduit 151 and a lower water gauge conduit 152, the upper water gauge conduit 151 being disposed above the countercurrent Water inlet 136 of the carbon dioxide absorber 131 so that the level of the fluid in the absorber 131 can be read on the sight gauge'as is clearly shown in Figure 6 of'the drawings.

A gasoutlet 153 at the uppermost'end of the absorbing chamber 133 is connected by an exhaust conduit 154 andan intermediate T-coupling 155 to the point 1 .02- on the T-coupling 100. The remaining opening156 of the inter- 17 mediate T-coupling clearly shown in Figure 6 of the dra ings is connected to the conduit 30 shown in the general arrangement of Figure 1.

A flow valve 157 in the exhaust conduit 154 will control the flow of unabsorbed gases to the intermediate T-coupling 155, as it is possible to include an alternate arrangement to allow the unabsorbed combustion gases to pass directly to the flexible connecting conduit 10. This is accomplished by an alternate conduit 158 mounted between the exhaust conduit 154 and the flexible connecting conduit 10 with an alternate flow control valve 159 therein as clearly shown in Figure 6.

Operation of the general arrangement with carbon dioxide removal The heat and gas producer 14" and the carbon dioxide absorber 131 are placed in the general arrangement as shown in Figure l in place of the heat and gas producer 14 by connecting them to the elements 10, 37, 34 and 30 as above described. The system is otherwisev unchanged;

Accordingly, for starting up, main control valve 11 is closed and the auxiliary start-up valve 12 is opened.

The prime mover is thereafter started causing the driving shaft to rotate the driven shafts 45, 46 and 47 of the water pump 32, air compressor 36 and fuel gas compressor 39 whereby water, air and fuel-gas can be passed to the respective conduits 34, 37 and 30 to the air outlet 93, the fuel gas outlet 94 and the cooling-water inlet 156 respectively connected thereto as the valves 35, 37 and 31 are opened manually.

The cooling water valve 31 will first be opened to allow cooling water to pass through conduit 30 to the cooling water inlet 156 of the intermediate T-coupling 155 which in turn directs it through the point 102 on the T-coupling 100. The water then passes to the upper cooling-water inlet 98 and the lower cooling-water inlet 99, the greater quantity of water passing upwardly through the upper cooling water inlet 98 of the cooling water jacket 96 by reason of the orifice 103. r I

The cooling water then pases to the cooling water outlet 104 which communicates by the flexible conduit 10 with the auxiliary start-up valve 12 which is open and allows the water to pass to waste or reservoir (not shown).

Combustion is commenced at low pressure by opening the air valve 35 and fuel gas valve 38 to allow air and fuel gas in proper mixture to be pumped into the combustion chamber 91 through the air outlet 93 and fuel gas output 94. The ignition means 95 will be used initially to start combustion until the temperature and presthese higher pressures to form carbonated water. The remaining combustion gases which consist mainly of nitrogen will be passed out of the carbon dioxide absorber 131 through the gas outlet 153 wherever it may be directed to be joined with the cooling water before it passes to the cooling water inlets 98 and 99 by opening flow valve 157 or it may be joined with the cooling water after it is converted to superheated steam by heat exchange relationship in the cooling jacket 96 of the heat and gas producer 14" by closing valve 157 and opening auxiliary flow control valve 159 connected to the flexible connecting conduit 10.

In either case a gas and superheated steam mixture will be produced which is substantially free of carbon dioxide which can be passed from the flexible connecting conduit 10 to the input conduit 2 of the input well A by slowly closing the auxiliary start-up valve 12 and simultaneously or approximately so opening the main valve 11. This mixture can act when it reaches input well A similar to a pneumatic drive with the added properties and effect of the heating of the oil-bearing formation or strata as above described in connection with the general arrangement as shown in Figure 1.

Superheated steam When it is desired to produce only superheated steam,

the heat and gas producer 14" will have its exhaust outlet 106 coupled with a heat exchanger through which the cooling water is passed to preheat it prior to being directed to the cooling water jacket 96 where by further heat exchange relation it is changed into the desired superheated steam state.

Referring to Figure 7, this type of apparatus is shown wherein the coupling means 107 of the exhaust outlet 106 is connected by an elbow type conduit 160 to a heat exchanger 161.

The heat exchanger 161 may be any conventional type of heat exchanger easily purchasable on the open market and which generally includes an inlet chamber 162 continuous with the elbow type conduit 160 to receive the combustion products therein. The inlet chamber 162 is connected to an outlet chamber 163 by a series of hollow metal tubes 164 so that combustion products can pass sure is high enough to sustain spontaneous combustionas above described.

The combustion products will be passed from the com bustion chamber 91 through the connecting conduit 130 connected to the outlet 106 thereof to the carbon dioxide absorber 131 and the back pressure thereof can be regulated by opening one or the other of the flow control valves 157 and 159.

When the back pressure becomes sufficiently high the pump 137 can be started to force countercurrent water to flow into the carbon dioxide absorber 131 through the countercurrent water inlet 136 connected thereto. The entire absorbing chamber 133 will be filled with this countercurrent water by the action of gravity, by controlling the expander valve 145 and by controlling the back pressure of the non-absorbed combustion products till the level is maintained at L on the water sight 'gauge150. This is determined empirically for the particular apparatus.

The pressure and temperature in the system is allowed to increase slowly. By reason of the differential pressure the combustion products will be forced upwardly through the countercurrent water in countercurrent flow relationship. Carbon dioxide will be absorbed by the water at freely from the inlet chamber 162 to the outlet chamber 163 whence they are led off by an exhaust conduit 164 communicating with the outlet chamber 163, a suitable control valve 165 is provided to control the back pressure in the combustion chamber and to control the flow of combustion products therethrough either to waste or a suitable reservoir for use. I 7

The heat exchanger 161 also includes a chamber which surrounds the tubes 164 havinga cooling water inlet 167 which is connected to the water conduit 30 shown in the general arrangement of Figure 1 of the drawings. A cooling water outlet 168 for the chamber 166 is connected by a connecting conduit 169 to the point 102 on the T- coupling. Thus cooling water can be brought into the chamber 166 through the cooling water inlet 167 and passed out of the chamber 166 through the cooling water outlet 168 which allows it to enter into heat exchange relationship with the tubes 164. Baffles 170 are provided to increase the time of contact of the cooling water with the tubes 164.

Operation of general arrangement for superheated steam The heat and gas producer 14" and the heat exchanger 161 are placed in the general arrangement asshown in Figure 1 in place of the heat and gas producer 14 by connecting them to the elements 10, 37, 34 and 30 as above described. The system is otherwise unchanged.

For starting up the main control valve 11 is closed and the auxiliary start-up valve 12 is opened. All the remaining valves are normally closed.

The prime mover 40 is started which operates the water pump 32, the air compressor 36 and the fuel gas 19 compressor 39 as above described in connection with the general arrangement.

The water valve is opened which allows cooling water to pass from the water pump 32 through the conduit 30 to the inlet 167 of the chamber 166 on the heat exchanger 161. It is forced out of the heat exchanger 161 at the outlet 168 and thence through the connecting conduit 169 to the T-coupling 100. From the T-coupling it will flow to the upper cooling-water inlet 98 and the lower cooling-water inlet 99 of the cooling jacket 96 on the heat and gas producer, the greater quantity of cooling Water being forced to the upper cooling Water inlet 93 by reason of the orifice 103.

The cooling water will pass from the cooling water jacket 96 to the flexible connecting conduit through the cooling Water outlet 104 connected therebetween and thence through the auxiliary start-up valve 12 to waste or a reservoir (not shown).

After the cooling water starts to flow from the auxiliary start-up valve, the air valve 35 and fuel gas valve 38 are opened and air and fuel gas are passed through conduits 34 and 37 to the air outlet 93 and fuel gas outlet 94 into the combustion chamber fil where they are ignited by the ignition means 95.

The pressure is allowed to increase to at least 1400 p. s. i. a. by regulating the control valve 165 and at this pressure suflicient heat is produced to cause the cooling water to be changed to superheated steam, it being me heated in the heat exchanger 161 and then absorbing further heat by heat exchange relationship in the cooling water jacket 96.

As the superheated steam is formed the auxiliary start-up valve 12 is closed and the main valve 11 is opened simultaneously or approximately so therewith to pass the superheated steam to the input conduit 2 connected to the flexible connecting conduit 16 and hence to the well A, where it can heat up and drive the residual oil in the oil-bearing formation or strata.

It is understood that although the method and apparatus has been particularly described with reference to the form and arrangements of parts precisely as shown herein that those skilled in the art may vary the details of construction as well as the precise arrangement of parts without departing from the spirit of this invention and, therefore, the invention is not to be limited to these specific constructions or arrangements of parts shown, but that they may be widely modified within the invention defined by the claims.

What is claimed is:

1. Apparatus for recovery of oil from oil bearing formations having at least one input Well and a producing well therein in spaced relation thereto comprising, a combustion chamber, an air outlet and a fuel outlet concentric therewith opening into said combustion chamber, compressing means for supplying air to said air outlet at pressures limited by the depth of the oil-bearing formation, compressing means for supplying fuel gas to said fuel outlet at pressures limited by the depth of the oilbearing formation, ignition means in said combustion chamber for starting initial combustion of the air and fuel mixture passed from said outlets into said combustion chamber, a cooling jacket about said combustion chamber having an inlet near the combustion end of said combustion chamber, pumping means for delivering cooling water to said cooling jacket inlet at pressures in excess of the pressures in said combustion chamber, an outlet for said cooling jacket opening into said combustion chamber at a point remote from said combustion end of the combustion chamber, an outlet for said combustion chamber remote from the air and fuel gas outlets, evaporating plates circumferentially mounted in said combustion chamber between said outlets for retaining portions of said cooling water to allow them to absorb enough heat to pass to the steam state, and flexible conduit connected between said combustion chamber outlet and at least one of said 20 input wells for continuously leading the gas and superheated steam mixture formed in said combustion chamber from the combustion products and the cooling water down said input well to the oil-bearing formation to allow said mixture to act on the residual oil in the oil-bearing formation and move it to the producing Well.

2. Apparatus for recovering oil from an oil-bearing formation having at least one input well and a producing well therein in spaced relation to each other comprising, a heat and gas producer having a combustion chamber, a water gas reaction zone and a mixing chamber in operative relationship for producing a gas and superheated steam mixture having reducing properties, compressing means for continually supplying air and excess fuel gas to said combustion chamber at pressure limited by the depth of the oil-bearing formation for continuous combustion in said combustion chamber to form combustion products at high temperature and substantially at the limiting pressure, a cooling jacket for said heat and gas producer extending about the combustion chamber, the Water gas reaction zone and the mixing chamber having an inlet, pumping means for delivering cooling water to said cooling jacket at pressures in excess of the pressures in said combustion chamber, a first outlet for said cooling jacket communicating with said water-gas reaction zone to allow cooling water to expand into the water-gas reaction zone to undergo the water-gas reaction with the combustion products in the combustion chamber, a second outlet for said cooling jacket communicating with said mixing chamber to allow cooling water to enter the mixing chamber and to form the gas and superheated steam mixture with reducing properties with the product of the Water-gas reaction zone, and conduit means connecting said mixing chamber to at least one of said input wells for leading the said mixture down the input well for contact with the oil-bearing formation to move residual oil in the oil-bearing formation into said producing well.

3. Apparatus for recovering oil from an oil-bearing formation having at least one input Well and a producing well therein in spaced relation to each other comprising, a heat and gas producer having a combustion chamber, a water-gas reaction zone and a mixing chamber in operative relationship for producing a gas and superheated steam mixture having reducing properties, compressing means for continually supplying air and excess fuel gas to said combustion chamber at pressures limited by the depth of the oil-bearing formation for continuous combustion in said combustion chamber to form combustion products at high temperature and substantially at said limiting pressure, a cooling jacket for said heat and gas producer extending about the combustion chamber, the water-gas reaction zone and the mixing chamber having an inlet, pumping means for delivering cooling water to said cooling jacket at pressures in excess of the pressures in said combustion chamber, a first outlet for said cooling jacket communicating with said water-gas reaction zone to allow cooling water to expand into the water-gas reaction zone to undergo the water-gas reaction with the combustion ,products in the combustion chamber, a second outlet for said cooling jacket communicating with said mixing chamber to allow cooling water to enter the mixing chamber and to form the gas and superheated steam mixture with reducing properties with the product of the water-gas reaction zone, and conduit means connecting said mixing chamberto at least one of said input wells for leading the said gas and superheated steam mixture down the input well for contact with the oilbearing formation to allow residual oil in said oil-bearing formation to be moved into said producing well.

4. Apparatus for the recovery of oil from an oilbearing formation having at least one input well and a producing well therein in spaced relation to each other comprising, a heatand gas producer having a combustion chamber at one end, a mixing chamber at the other end and a water-gas reaction zone providing communication 21 between said combustion and said mixing chambers, and said water-gas reaction zone having walls continuous with the combustion chamber and a restricted outlet entering and communicating with the mixing chamber, compressing means for continually supplying air and excess fuel gas to said combustion chamber at pressures limited by the depth of the oil-bearing formation for continuous combustion in said combustion chamber to form combustion products at high temperature and substantially at said limiting pressure, a cooling jacket for said heat and gas producer extending about the combustion chamber, the water-gas reaction zone and the mixing chamber having an inlet, pumping means for delivering cooling water to said jacket at pressures in excess of the pressures in the combustion chamber, a first outlet for said cooling jacket communicating with the combustion chamber just above the water-gas reaction zone to allow cooling water to expand into the water-gas reaction zone to undergo the water-gas reaction with the combustion products of the air and excess fuel gas mixture, a first group of circumferentially-mounted evaporating plates in said watergas reaction zone, means in said mixing chamber for catalyzing the water-gas reaction, a second outlet for said cooling jacket communicating with said mixing chamber below said last mentioned means to allow the remaining cooling water to expand into the mixing chamber and to form a gas and superheated steam mixture with reducing-properties with the products of the water-gas reaction, a second group of circumferentially-mounted evaporating plates in said mixing chamber below said second outlet, and a flexible conduit means connecting said mixing chamber to at least one of said input wells for leading said gas and superheated steam mixture down said input well to the oil-bearing formation to-move residual oil in said oil-bearing formation into said producing well.

5. Apparatus as claimed in claim 4 wherein said means for catalyzing the water-gas reaction includes a semi-spherical support plate transversely mounted in said mixing chamber above said second outlet for the cooling jacket, and material adapted to support catalyzing action carried by said support plate and filling a substantial portion of the mixing chamber between the restricted exit of the water-gas reaction zone and the semi-spherical support plate.

6. Apparatus for recovering oil from an oil-bearing formation having at least one input well and a producing Well therein in spaced relation to each other comprising, a combustion chamber, compressing means for continually supplying air and fuel gas to said combustion chamber at pressures limited by the depth of the oil-bearing formation for continuous combustion in said combustion chamber to form combustion products at high temperature and substantially at the limiting pressure, an outlet for said combustion chamber, an absorption tower connected to said outlet to receive said combustion products therein, an inlet at the upper end of said absorption tower, pumping means for pumping water to said inlet at pressures slightly less than the pressures at which the comsaid oil-bearing formation to move residual oil therein bustion products enter said absorption tower, an outlet at the lower end of said absorption tower to allow the water to flow in countercurrent with the combustion products for selective absorption of carbon dioxide therefrom to form carbonated water, a waste outlet on said absorption tower for eliminating non-absorbed combustion products including nitrogen, a cooling jacket about said combustion chamber, spaced inlets for said cooling jacket communicating with said outlet for the absorption tower to conduct carbonated water to said cooling jacket to be brought into heat exchange relationship with said combustion chamber to raise it above its critical temperature for forming a gas and superheated steam mixture sub stantially free of nitrogen, an outlet for said cooling jacket, and a flexible conduit means connected to said outlet for continuously leading said gas and superheated steam mixture down at least one of said input wells to into the producing well.

7. Apparatus for recovering oil from an oil-bearing formation having at least one input well and a producing well therein in spaced relation to each other comprising, combustion chamber, compressing means for continually supplying air and fuel gas to said combustion chamber at pressures limited by the depth of the oil-bearing formation for continuous combustion in said combustion chamber to form combustion products at high temperature and substantially at said limited pressures, an outlet for said combustion chamber, an absorption tower connected to said outlet to receive said combustion products therein, an inlet at the upper end of said absorption tower, pumping means for pumping water to said inlet at pressures slightly less than the pressures at which the combustion products enter said absorption tower, an outlet at the lower end of said absorption tower to allow the water to flow in countercurrent with the combustion products for selective absorption of carbon dioxide therefrom to form carbonated water, a waste outlet on said absorption tower for eliminating non-absorbed combustion products including nitrogen, a cooling jacket about said combustion chamber, an upper and lower inlet for said cooling jacket communicating with said water outlet for the absorption tower to conduct carbonated Water to said cooling jacket, means in said lower inlet for directing a relatively larger ratio of the carbonated cooling water to the upper inlet for the cooling jacket so that the carbonated water will pass about the upper and hotter end of the combustion chamber to absorb by heat exchange relationship therewith sufficient heat to raise it above its critical temperature and form a gas and superheated steam mixture substantially free of nitrogen, an outlet for said cooling jacket, a flexible conduit means connecting said cooling jacket to at least one of said input wells to lead said gas and superheated steam mixture down said well for contact with the oil-bearing formation to move residual oil therein into said producing well.

8. Apparatus as claimed in claim 7 wherein said means in the lower inlet includes an orifice transversely mounted in said lower inlet and sized in accordance with the desired ratio of water to be directed to said upper inlet.

9. Apparatus for recovering oil from an oil-bearing formation having at least one input well and a producing well therein in spaced relation to each other comprising a combustion chamber, compressing means for continually supplying air and fuel gas to said combustion chamber at pressures limited by the depth of the oil-bearing formation for continuous combustion'in said combustion chamber to form combustion products at high temperature and substantially at said limiting pressure, an outlet for said combustion chamber, an absorption tower including an absorption chamber therein, an inlet for said absorption chamber connected to said outlet for receiving combustion products at high temperature and substantially limiting pressure, an injection nozzle continuous with said inlet for passing the combustion products centrally upward through said absorption chamber, means for increasing the absorption area in said absorption chamber, and a waste outlet for directing non-absorbed combustion products to atmosphere, a water inlet for said absorption chamber at the upper end thereof, pumping means connected to said inlet for delivering water to said inlet at pressures slightly less than the pressure of the combustion products entering the absorption chamber, a water outlet for said absorption chamber between said injection nozzle and said means to displace said water by gravity flow in countercurrent with said combustion products to form carbonated water by selective absorption of carbon dioxide from the combustion products, a cooling jacket about said combustion chamber having an upper inlet and a lower inlet, said upper inlet and said lower inlet connected to the Water outlet for the absorption chamber to allow carbonated water to be directed as a coolant in said cooling jacket, an orifice in said lower inlet to direct the greater quantity of cooling water to the upper or hotter end of the combustion chamber to enable the same to absorb by heat exchange relationship sufficient heat to raise it above its critical temperature and to form a gas and superheated steam mixture substantially free of nitrogen, an outlet for said cooling jacket, and a flexible conduit means for connecting said cooling jacket to at least one of said inlet wells for leading the gas and superheated steam mixture down said inlet well to said oilbearing formation to move residual oil therein into said producing well.

10. Apparatus as claimed in claim 9 wherein the means for increasing the absorption area in the absorption chamber includes a transversely mounted perforated support plate near the lower end of the absorption chamber, and surface increasing elements supported by said support plate filling the greater portion of the absorption chamber just short of the water inlet therefor.

11. Apparatus for recovering oil from an oil-bearing formation having at least one input well and a producing well therein in spaced relation to each other comprising, a combustion chamber, compressing means for continually supplying air and fuel gas to said combustion chamber at pressures limited by the depth of the oilbearing formation for continuous combustion in said combustion chamber to form combustion products at high temperature and substantially at said limiting pressure, an outlet for said combustion chamber, a carbon dioxide absorber connected to said outlet to receive said cornbustion products therein, an inlet at the upper end of said absorber, pumping means for pumping water to said inlet at pressures slightly less than the pressures at which the combustion products enter said absorber, an outlet at the lower end of said absorber to allow the water to flow in countcrcurrent with the combustion products for selective absorption therefrom of carbon dioxide to form carbonated water, a storage tank, means for passing said carbonated water to said storage tank through a reducing valve to eliminate the carbon dioxide to atmosphere, a cooling jacket for said combustion chamber having an upper and a lower inlet, pumping means taking its suction from said storage tank for delivering cooling water to said inlets, an outlet for non-absorbed combustion products in said absorber connected between said pumping means and said inlets to join said non-absorbed combustion products with the cooling water, means in said lower inlet for passing the greater portion of said cooling water to the upper inlet to pass the same about the upper end of the cooling jacket in heat exchange relationship with the hottest portion of the combustion chamber to heat said cooling water above its critical temperature and to form a gas and superheated steam mixture substantially free of carbon dioxide, an outlet for said cooling jacket, and a flexible conduit connecting said cooling jacket to at least one of said input wells for continuously supplying said gas and superheated steam mixture to said input well for contact with said oil-bearing formation to move residual oil therein into said producing well.

12. Apparatus for recovering oil from an oil-bearing formation having at least one input well and a producing Well therein in spaced relation to each other comprising, a combustion chamber, compressing means for continually supplying air and fuel gas to said combustion chamber at pressures limited by the depth of the oil-bearing formation for continuous combustion in said combustion chamber to form combustion products at high temperature and substantially at said limiting pressure, an outlet for said combustion chamber, a carbon dioxide absorber connected to said outlet to receive said combustion products therein, an inlet at the upper end of said absorber, pumping means for pumping water to said inlet at pressures slightly less than the pressures at which the com bustion products enter said absorber, an outlet at the lower end of said absorber to allow the water to flow in countercurrent with the combustion products for selective absorption therefrom of carbon dioxide to form carbonated water, a storage tank, means for passing said carbonated water to said storage tank through a reducing valve to eliminate the carbon dioxide to atmosphere, a cooling jacket for said combustion chamber having an upper and a lower inlet, pumping means taking its suction from said storage tank for delivering cooling water to said inlets, means .in said lower inlet for directing the greater portion of said cooling Water to the upper inlet to pass the same about'the upper end of the cooling jacket heat exchange relationship with the hottest end of the combustion chamber to raise the temperature of the cooling water above its critical temperature to form superheated steam, an outlet for said cooling jacket, a flexible conduit means connecting said outlet with at least one of said input wells, an outlet for non-absorbed combustion products in said absorber connected to said flexible conduit past said outlet for the cooling jacket to allow said non-absorbed products to join with the superheated steam to form a gas and superheated steam mixture substantially free of carbon dioxide, said flexible conduit so constructed and arranged that said gas and superheated steam mixture is brought continuously to the bottom of said input well into contact with said oil-bearing formation to move residual oil therein into said producing well.

13. Apparatus for recovering oil from an oil-bearing formation having at least one input well and a producing well therein in spaced relation to each other comprising, a combustion chamber, compressing means for continually supply air and fuel gas to said combustion chamber at pressures limited by the depth of the oil-bearing formation for continuous combustion to form combustion products at high temperature and substantially at said limiting pressure, an outlet for said combustion chamber, a heat exchanger including an inlet connected to said outlet for receiving combustion products from said combustion chamber, tubes in said heat exchanger for allowing said combustion products to pass therethrough, an outlet for said combustion products having a valve for regulating the back pressure of said combustion products, and a chamber about said tubes having a water inlet and a water outlet to conduct cooling water in heat exchange relationship with said tubes to preheat the same, pumping means connected to said water inlet for pumping water under pressure through said chamber, a cooling jacket for said combustion chamber having an upper inlet and a lower inlet for cooling water, said water outlet communicating with said upper and lower inlets for the cooling jacket, means in said lower inlet for forcing the greater portion of cooling water to said upper inlet to allow said preheated cooling water to enter into heat exchange relationship with the upper and hotter end of the combustion chamber to form superheated steam, an outlet for said cooling jacket, a flexible connecting conduit connecting sa d outlet to at least one of said input wells for continuously leading superheated steam down said input well for contact with the oil-bearing formation to move residual oil therein into said producing well.

14. Apparatus as claimed in claim 13 wherein said means in the lower inlet for directing the greater portion of the preheated cooling water to the upper inlet includes an orifice transversely mounted therein, and said orifice sized in accordance with the desired ratio of water to be directed to the upper inlet.

15. The method of recovering oil from an oil bearing formation having at least one input well and a producing well therein in spaced relation to each other which consists in delivering air and fuel at a pressure limited by the depth of the oil bearing formation to a combustion chamber positioned at the surface, combusting the air and fuel in said combustion chamber to form high temperature combustion products including nitrogen and carbon dioxide at substantially the limiting pressure, forcing the combustion products to an absorbing tower, pumping water into said absorbing tower at pressures slightly less than the pressures of the incoming combustion products, passing the water and combustion products in counterflow relationship by pressure differential and action of gravity to form carbonated water by selective absorption of the carbon dioxide during such countercurrent flow, expanding the unabsorbed portion of the combustion products including nitrogen to atmosphere, passing the carbonated water in heat exchange relation with the wall of said combustion chamber to control the temperature of said combustion products and to simultaneously heat said carbonated water above the critical temperature thereof to form a gas and superheated steam mixture substantially free of nitrogen, continuously passing the said gas and superheated steam mixture down at least one input well to contact the oil in the oil bearing formation, and operating the producing well for recovery of oil moved therein under action of the gas superheated steam mixture substantially free of nitrogen.

16. The method of recovering oil from an oil bearing formation having at least one input well and a producing well therein in spaced relation to each other which con sists in delivering air and fuel at a pressure limited by the depth of the oil bearing formation to a combustion chamber positioned at the surface, combusting the air and fuel in said combustion chamber to form combustion products including nitrogen and carbon dioxide at substantially the limiting pressure, forcing the combustion products to a carbon dioxide absorber, pumping water into said absorber at pressures slightly less than the pressures of the incoming combustion products, passing the water and combustion products in counterflow relation by pressure differential and action of gravity to form carbonated water by selective absorption of the carbon dioxide during such counterflow, expanding the carbonated water to release substantially all of the carbon dioxide dissolved therein, passing the water in heat exchange relation with the Wall of said combustion chamber to control the temperature of said combustion products and to simultaneously heat said water above its critical temperature to form steam, joining the unabsorbed portion of the combustion products from the carbon dioxide absorber with this steam to form a gas and superheated steam mixture substantially free of carbon dioxide, and continually injecting the mixture down the input well to act on oil and the oil bearing formation and to move it therefrom into the producing well for recovery.

17. Apparatus for recovery of oil from oil bearing formations having at least one input well and a producing well therein in spaced relation thereto comprising, a combustion chamber, said combustion chamber having a fuel inlet at one end and an air inlet concentric of said fuel inlet, compressing means to supply air to said air inlet at predetermined pressures, compressing means to supply fuel gas to said fuel inlet at predetermined pressures, ignition means in said combustion chamber adjacent said inlets for starting combustion of the air and fuel mixture delivered through said inlets to the combustion chamber, a cooling jacket about said combustion chamber having its inlet for cooling water at the end of said cooling jacket about the air and fuel inlets in said combustion chamber, pumping means for delivering cooling water to said cooling jacket inlet at pressures in excess of the pressures in said combustion chamber, said cooling jacket having an outlet opening communicating with said combustion chamber at the end remote from the air and fuel inlets to form in said combustion chamber a mixture of combustion gases and superheated steam at pressures less than the pressures required to separate the overburden from the oil bearing formation, said combustion chamber having a discharge outlet at said end remote from the air and fuel gas inlets for said mixture, and flexible conduit means connected between said combustion chamber outlet and at least one of said input wells for continuously leading the gas and superheated steam mixture formed in said combustion chamber from the combustion products and cooling water down said input well to the oil-bearing formation to allow said mixture to act on oil in said oil-bearing formation to force the same towards the producing well.

18. Apparatus for recovery of oil from oil-bearing formations having at least one input well and a producing well therein in spaced relation thereto comprising, a combustion chamber positioned at the surface of said oilbearing formation, said combustion chamber having a fuel inlet at one end and an air inlet concentric of said fuel inlet, compressing means to supply air to said air inlet at predetermined pressures, compressing means to supply fuel gas to said fuel inlet at predetermined pressures, ignition means in said combustion chamber adjacent said inlets for starting combustion of the air and fuel mixture delivered through said inlets to the combustion chamber, a cooling jacket about said combustion chamber having its inlet for cooling water at the end of said cooling jacket about the air and fuel inlets in said combustion chamber, pumping means for delivering cooling water to said cooling jacket inlet at pressures in excess of the pressures in said combustion chamber, said cooling jacket simultaneously controlling the temperature of said combustion products whereby the cooling water in the jacket is heated above its critical temperature to form steam, said cooling jacket having an outlet communicating with the combustion chamber at the end remote from said air and fuel inlets to form in said combustion chamber a mixture of combustion gases and superheated steam at pressures determined by the overburden of the oil bearing formation, said combustion chamber having a discharge outlet at said end remote from the air and fuel gas inlets, and flexible conduit means connected between said combustion chamber outlet and at least one of said input wells for continuously leading the gas and superheated steam mixture formed in said combustion chamber from the combustion products and cooling water down said input well to the oil-bearing formation to allow said mixture to act on oil in said oil-bearing formation to force the same towards the producing well.

19. Apparatus for recovery of oil from oil-bearing formations having at least one input well and a producing well therein in spaced relation thereto comprising, a combustion chamber, said combustion chamber having a fuel inlet at one end and an air inlet concentric of said fuel inlet, compressing means to supply air to said air inlet at predetermined pressures, compressing means to supply fuel gas to said fuel inlet at predetermined pressures, ignition means in said combustion chamber adjacent said inlets for starting combustion of the air and fuel mixture delivered through said inlets to the combustion chamber, a cooling jacket about said combustion chamber having its inlet for cooling water at the end of said cooling jacket about the air and fuel inlets in said combustion chamber,

pumping means for delivering cooling water to said cooling jacket inlet at pressures in excess of the pressures in said combustion chamber, said cooling jacket having an outlet opening communicating with said combustion chamber at the end remote from the air and fuel inlets to form in said combustion chamber a mixture of combustion gases and superheated steam at pressures less than the pressures required to separate the overburden in the oil-bearing formation, said combustion chamber having a discharge outlet at said end remote from the air and fuel gas inlets for said mixture, scrubbing means connected to said discharge outlet to receive the gas and superheated steam mixture therethrough for removing the soot component of the combustion products in said mixture, and flexible conduit means connected between said scrubbing means and at least one of said input wells for continuously leading the soot-free gas and superheated steam mixture down said input well to allow said mixture to act on oil in said oil-bearing formation to force the same towards the producing well.

20. Apparatus as claimed in claim 19 wherein said scrubbing means includes a pair of elongated hollow cylinders having inlet ends adapted to be alternately connected to said outlet for the combustion chamber for leading the gas and superheated steam mixture into said elongated cylinders, each of said elongated cylinders including a cylindrical supporting chamber open towards the inlet end and mounted in spaced relation in said elongated chamber to form annular passages therebetween in each of said elongated cylinders, filter means carried in each of said supporting chambers, circumferentially spaced passages adjacent the ends of said supporting chambers remote from the inlet ends of the elongated cylinders to provide communication between said supporting chambers and said annular passages, and outlets for said annular passages connected to said flexible conduits.

References Cited in the file of this patent UNITED STATES PATENTS l 1 I l 

15. THE METHOD OF RECOVERING OIL FROM AN OIL BEARING FROMATION HAVING AT LEAST ONE INPUT WELL AND A PRODUCING WELL THEREIN IN SPACED RELATION TO EACH OTHER WHICH CONSISTS IN DELIVERING AIR AND FUEL AT A PRESSURE LIMITED BY THE DEPTH OF THE OIL BEARING FORMATION TO A COMBUSTION CHAMBER POSITIONED AT THE SURFACE, COMBUSTING THE AIR AND FUEL IN SAID COMBUSTION CHAMBER TO FORM HIGH TEMPERATURE COMBUSTION PRODUCTS INCLUDING NITROGEN AND CARBON DIOXIDE AT SUBSTANTIALLY THE LIMITING PRESSURE, FORCING THE COMBUSTION PRODUCTS TO AN ABSORBING TOWER, PUMPING WATER INTO SAID ABSROBING TOWER AT PRESSURES SLIGHTLY LESS THAN THE PRESSURES OF THE INCOMING COMBUSTION PRODUCTS, PASSING THE WATER AND COMBUSTION PRODUCTS IN COUNTERFLOW RELATIONSHIP BY PRESSURE DIFFERENTIAL AND ACTION OF GRAVITY TO FORM CARBONATED WATER BY SELECTIVE ABSORPTION OF THE CARBON DIOXIDE DURING SUCH COUNTERCURRENT FLOW, EXPANDING THE UNABSORBED PORTION OF THE COMBUSTION PRODUCTS INCLUDING NITROGEN TO ATMOSPHERE, PASSING THE 